Problem installing every plugins

Hi evreybody, whenever I try to install a new plug ins or update an existing one, at the end of the download I got a red message "Class ZIP archive not found!" and plugin is not installed. I have downloaded the GRAV version 1.1.0 R2... any help?

Your PHP needs to have support for Zips. This is a PHP extension. Installing/enabling that depends on your platform: http://stackoverflow.com/questions/3872555/fatal-error-class-ziparchive-not-found-in

ok, otherwise I see I can install modules simply copy them to the appropriate directories :)